67 barracuda 383 #3/5

The car was idling with a couple of bumps for grins. sniper stealth EFI. So, new guy here, exhaust temp is 1162? I was using the lazer style temp gun a couple inches down from spark plug where I envisioned a cylinder to be. The drinkers side was 250-300, but #3/5 were 6-700. Im not too excited about it as the thing needs shaking down, I just got it started. I have been led to believe this is a 9.5:1 compression.....but I really dont know. engine came with the car in boxes, Im just putting it together.